First direct mass measurement for neutron-rich Mo 112 with the new ZD-MRTOF mass spectrograph system

Abstract

The atomic masses of Ag111,113, Pd111-113, Rh111-113, Ru111-113, and Mo111,112 have been measured during the online commissioning experiments of the ZeroDegree multi-reflection time-of-flight Mass Spectrograph (ZD MRTOF-MS) at the RIKEN RI beam factory. The mass of Mo112 has been determined. For the previously known masses, a good agreement between our results and the 2020 Atomic Mass Evaluation has been observed in most cases. The determined two-neutron separation energies for Mo isotopes up to N=70 show a smooth trend. In this work, the performed experiment and analysis procedure are presented. The theoretical interest in the measured region is highlighted, and the results are discussed in terms of the various mass surface formulas including the new mass data. Furthermore, a comparison between our results and global theoretical mass models is given, and we provide a benchmark for results from a Bayesian machine learning algorithm for future mass extrapolation.